We are characterizing proteins involved in disorders affecting the nervous system to permit the isolation of cDNA and genomic DNA that can be used to develop treatments disorders using gene transfer. Particularly suited for initial attempts at gene therapy are those disorders where the systemic and in some instances even the neurologic manifestations of the disorder are treatable using recombinantly altered, accessible bone marrow, fibroblast, hepatic, or endothelial derived cells. We have used the lysosomal disorder Gaucher disease as a prototype to develop more efficient gene transfer, particularly using mouse models. Recently we have produced a long lived, mildly affected, mouse model of Gaucher disease by homologous recombination in embryonic stem cells. Retroviral vectors have been used to express human glucocerebrosidase and other genes in mouse and patient cell lines and tissues, and to reverse storage of lipid in tissues in murine models of Gaucher disease. In addition, receptor, liposome, oligonucleotide, adeno-associated virus (AAV) and lentivirus mediated DNA transfer into specific tissues are among strategies being investigated. In utero treatments in mice may be required for effective treatment of disorders affecting the nervous system where tissue damage occurs early in gestation. An initial goal of this research is the application of gene therapy to the non-neuronopathic phenotypes of disorders that can, in some cases, also affect the nervous system. We have also used retroviral mediated transfer of neurotransmitter synthesizing enzymes such as tyrosine hydroxylase for both the in-vitro and in-vivo correction of DOPA deficiency states. Recombinantly engineered cells (for instance, fibroblasts) producing tyrosine hydroxylase have been used as depots of L-DOPA release and have been transplanted into the nervous system of animal models. When our understanding of the pathogenetic mechanisms of inherited neurologic and psychiatric disease improves and as technologies for the transfer and expression of genes in specific tissues and cells becomes more predictable, we should be able to extend the use of gene therapy to treatment of a larger number of disorders affecting the nervous system.